Process for the manufacture of bis(benzot hiazylsulphene) amides

ABSTRACT

Bis-(benzothiazylsulphene)amides of formula:   WHERE R is a hydrocarbon radical, are obtained by treating a benzothiazylsulpheneamide of formula:   WITH AN ORGANIC ACID ANHYDRIDE HAVING A STRUCTURAL FORMULA WHICH INCLUDES AT LEAST ONE RING, E.G., PHTHALIC OR MALEIC ANHYDRIDE.

United States Patent Maison [451 Apr. 1, 1975 PROCESS FOR THEMANUFACTURE OF BIS( BENZOT HIAZYLSULPHENE)AMIDES Related US. ApplicationData Continuation of Ser. No. ll0,745, Jan. 28, 1971, abandoned.

Inventor:

Foreign Application Priority Data Jan. 30, 1970 France 70.0335l US. Cl260/306.6 A, 260/4, 260/785 Int. Cl C07d 91/48 Field of Search 260/306.6A

References Cited UNITED STATES PATENTS ll/l958 Conly 260/306.6 A

Primary Examiner-Richard J. Gallagher Attorney, Agent, or FirmStevens,Davis, Miller & Mosher [5 7 ABSTRACT Bis-(benzothiazylsulphene)amides offormula:

where R is a hydrocarbon radical, are obtained by treating abenzothiazylsulpheneamide of formula:

with an organic acid anhydride having a structural formula whichincludes at least one ring, e.g., phthalic or maleic anhydride;

6 Claims, No Drawings ring can also originate from two carboxyl groupsin an PROCESS FOR THE MANUFACTURE OF rather repidly and within a smallvolume which gives a BIS(BENZOT HIAZYLSULPHENDAMIDES high productivityfor the apparatus. This is a continuation of application Ser. No.Reaction between reagents which are solid at the rell( ,745, filed Jan.28, 1971, and now abandoned. action temperature can be improved bycarrying out The present invention relates a new process for the 5 theprocess in the presence of a solvent which is inert manufa tur fbis-(benz hi zyl ulph ne)ami towards the reagents under the conditionsemployed.

Bls'(bchzhthluzylsulphehe)hmldes have been Suitable solvents includehydrocarbons such as cycloscribed in Pat. Spec. NO. and are usefulhexane benzene aliphatic petrols n heptane or halo- 21S flCCClCI'EltOI'SfOI' thC vulcanisation Of natural OI syngenated solvents where thehalogen atom is of low reacthC C C l0 tivity, such as carbontetrachloride or chlorobeiizene. The Present lhvehtloh Provldes 11lih'oceSS the If the solvent boils at the temperature used, it will bePreparation of bls'(behzhthlazylsulphehe)ahhdes of convenient to carryout the process so that the vapours general formula: of the solventreflux.

A molar ratio of monosulpheneamide/anhydride group of about 2 is used.Generally, a slight excess of anhydride (for example up to about allowsthe I i yield relative to the more costly product, themonosulpheneamide, to be improved. Furthermore, this allows a finalproduct almost free of monosulpheneamide to be obtained. The startingmonosulpheneamide can contain up to 10% of impurities withoutdisadvantage.

It is not essential for the reaction medium to be homogeneous to obtainthe bis-(benzothiazylsulphene)amide. Furthermore, traces of water do notunfavourably affect either the yield or the quality of the productobtained.

l The crude reaction product, freed of solvent if used, 5 Sum can beused as such as an accelerator for the vulcanisation of rubber mixtures,because the impurities present are practically inert towards rubber andonly behave as diluents. However, if desired, the greater part of thereaction by-products (acid amide, or amide and acid) can easily beremoved, as can a possible excess of anhydridc, by a treatment withalkali. For this purpose, the crude reaction product can be subjected tothe action of aqueous alkaline solution, e.g., an alkali metal hydroxidesolution or an ammonia solution, at about 10 to 30C; thebis(benzothiazylsulphene)amide remains insoluble in this medium, whilstthe other products present pass into solution.

in which the symbol R represents a hydrocarbon radical, by reaction of abenzothiazylsulpheneamide of general formula:

with an organic acid anhydride having a structural formula whichincludes at least one ring.

In the anhydridcs of cyclic formula, a ring can be bonded to the acylgroup, for example in aromatic carboxylic acid anhydrides such asbcnzoie anhydride. The

intramolecular anhydride, such as anhydridcs of aliphatic dicarboxylicacids containg 4 to 6 carbon atoms (for example maleic, succinic orglutaric ai'ihydrides). Condensed polycyclic anhydrides can also beused; these are intramolecular anh drides of aromatic car- I boxylicacids such as phthalic anhydride and pyronielh y phcne)amidcs obtainedacmic unhwiridu cording to process of the invention show a h gh lt ispreferred that R represent a linear or branched Smmgc f w h Posslhlc h"ulchhlsmhm alkyl radical of l to 12 carbon atoms. such as methyl,Speeds wlth 8' safety use, and p advantacthyL impmpyL goclyl or dummy],or a gyclm geo us mechanical properties (tensile strength and elonlk l dl i 5 to 6 ring carbm atoms Such as gation at break, and modulus at300%) to the vulcanclopentyl or cyclohexyl. ISCd P u ts. i I

The reaction takes place in accordance with the fol- The Examples WhlchlOllOW Il u trate the Invention.

. 5O lowing equation:

L. coma where-CO-XCO- represents either a diacyl radi- EXAMPLE 1 cal ortwo monovalent cyclic acyl radicals. 82 g of phthalic anhydride (055mol) and 264 g The reaction temperature depends on the reagentscyclnhcxylbenlothiazylsulpheneamide of 98% purity used. particularlytheir heat stability, their melting (repre enting 0.9? mol) areintroduced cold into a point and their reactivity and, where a solventis emmiXer equipped with a heating acket, and then stirred. ployed.their solubility. A suitable reaction tempera- The temperature of themixture is raised to l00C and ture is generally between 35 and C, andpreferamaintained at that temperature for 30 minutes; the bly between 60and l l()C. If the process is carried out mass thickness, becomes pastyand then solidifies and in the absence of solvents, the reaction takesplace crumbles.

The crumbled mass is cooled to 20C. The mixture obtained, which melts atbetween 120 and 140C, consists of excess phthalicanhydride;cyclohexylphthalamie acid andN-cyclohexyl-bis-(benzothiazylsulphene)amide. This mixture is treatedwith 1.1 litres of a normal aqueous sodium hydroxide solution for 2hours at 20C. Filtration, washing and drying gives 202 g ofcyc1ohexyl-bis (benzothiazylsulphene)amide, melting 132133C. The yieldis 93.8% relative to the crude N-eyelohexylbenzothiazylsulpheneamide.

The impurities in the crude product for practical purposes do not causeany reduction in the activity of the purified product, as is shown bythe comparative vulcanisation test described below:

The following mixing formulation (composition by weight) is used.

TABLE 1 Plasticiser (predominantly naphthenic oil.

' marketed under the trademark NAPTOLEN) 5 Resin (diolclinc polymermarketed under the trademark ESCOREZ) Micro-crystalline wax (mixture ofaliphatic I hydrocarbons) 'lrin ethyldihydroquinolinc polymerN-lsopropyl-N -phenyl-p-phenylenediaminc 1 Insoluble sulphur SeeN-Cyclohcx \'l-his( benzothiazylsulphene )amide Table 11 The followingresults are obtained (Table 11).

EXAMPLE 3 82 g of phthalic anhydride (0.55 mol) and 238 g oft-butyl-benzothiazylsulpheneamide of 98% purity (representing 0.98 mol)are introduced cold into a mixer equipped with a heatingjecket andstirred. The temperature of the mixture is raised to 100C and maintainedat that temperature for 1 hour. The mass initially thickens, becomespasty and then solidifies and crumbles. The resulting mixture ofphthalic anhydride, t-butylphthalamic acid andt-butyl-bis(benzothiazylsulphene)-amide is cooled to about 20C.

This mixture is treated with 1.1 litres of a normal aqueous sodiumhydroxide solution for 2 hours at 20C.

The bis-(su1phene)amide is filtered off, washed and dried. 194 g oft-butyl-bis-(benzothiazylsulphene)amide, melting at 141C, is obtained ina yield of 96% relative to the crude t-butyl-benzothiazylsulpheneamide.

EXAMPLE 4 54 g of maleic anhydride (0.55 mol) and 264 g ofcyclohexylbenzothiazylsulpheneamide of 96.8% purity (representing 0.968mol) are introduced cold into a mixer equipped with a heating jacket,and stirred. The temperature of the mixture is raised to 60C andmaintained at that temperature for minutes. The mass liquefies, becomesdeep green and then pasty, and thereafter solidifies and crumbles.

TABLE 11 MOONEY Vulcanisation in a Cyclohexyl-bis(benzoscorching timepress at 145C. thiazylsulphene)amide at 130C. optimum (in 300% modulus(minutes) minutes) (kg/cm) Product of Example 1, melting at 120-140C 4741 89 (1.8 part) Product of Example 1 purified by an aqueous alkalinetreatment 50 42 91 melting at l32133C.

(1 part) The products melting at 120-140C and at The resulting lightbeige mixture, melting at about 132133C show substantially the samesafety against scorching as the chemically pure product obtained byrecrystallisation from dimethylformamidc and melting at 136C. When 1part ofthe pure product, melting at 136C, is used under the conditionsof Table 11, the MOONEY scorching time is 51.5 minutes, indicating thatthe impurities in the product prepared according to the present processbehave simply as inert diluents.

EXAMPLE 2 1,000 cm of carbon tetrachloride, 82 g of phthalic anhydride(0.55 mol) and 264 g of cyelohexylbenzothiazylsulpheneamide of 98%strength (0.98 mol) are introduced into a flask equipped with a stirringdevice.

The mixture is heated at the reflux temperature and consisting of excessmaleic anhydride, cyclohexylmaleamic acid andN-cyclohexyl-bis(benzothiazylsulphene)amide, is cooled to 20C. Thismixture is treated with 1.1 litres of a normal aqueous sodium hydroxidesolution for 2 hours at 20C. Filtration, washing and drying yields 198 gof cyclohexyl-bis- (benzothiazylsulphene)amide melting at C. The yieldis 92.4% relative to the crude N-cyclohexylbenzothiazylsulpheneamide.

EXAMPLE The procedure of Example 4, is repeated replacing i only of92.9% purity, 195 g of cyclohexyl-bis-(benzothiazylsulphene)-amide,melting at l28-l30C, are obtained, representing a yield of 90.9%relative to the crude N-cyclohexylbenzothiazylsulpheneamide employed.

EXAMPLE 6 54 g of maleic anhydride (0.55 mol) and 238 g oftbutylbenzothiazylsulpheneamide of 92.2% purity (representing 0.922 mol)are introduced cold into a mixer equipped with a heatingjacket andstirred. The temperature of the mixture is raised to 100C and maintainedat that temperature for /2 hour. The mass becomes liquid and thenthickens, solidifies and crumbles. The resulting mixture of maleicanhydride, t-butyl-maleamic acid andt-butyl-bis-(benzothiazylsulphene)amide is cooled to about 20C.

This mixture is treated with 1.1 litres of a normal aqueous sodiumhydroxide solution for 2 hours at 20C. The bis-(sulphene)amide isfiltered off, washed and dried. 192 g oft-butyl-bis-(benzothiazylsulphene)amide, melting at l38l39C, areobtained, in a yield of 95.2% relative to the crudet-butyl-benzothiazylsulpheneamide employed.

I EXAMPLE 7 54 g of malcic anhydride (0.55 mol) and 224 g ofisopropylbenzothiazylsulphencamidc of 94.3% purity (representing 0.943mol) are introduced cold into a mixer equipped with a heating jacket andstirred. The temperature of the mixture is raised to 60C and main tainedat that temperature for l hour 20 minutes. The mass liquefies and thencools and crumbles in the mixer.

The light beige mixture obtained, which consists of maleie anhydridc.isopropylmaleamic acid and isopropyl-bis-(benzothiazylsulphenei-amidc iscooled to 20C.

This mixture is treated with 1.1 litres of a normal aqueous sodiumhydroxide solution at 20 for 2 hours.

Filtration. washing and drying yields 173 g of isopropyl-his-(benzothiazylsulphcne)amide melting at 100C, representing a yield of 89%relative to the crude N- isopropylbenzothiazylsulphcneamide employed.

EXAMPLE 8 If. in place of working at 60C as in Example 7, the process iscarried out at 40C, all other aspects being the same, the duration ofthe reaction must be extended to 4 hours 10 minutes (in place of 1 hourminutes). After treatment with sodium hydroxide, 180 g ofisopropyl-his-(benzothiazylsulphene)amidc, melting at 101C, areobtained, representing a yield of 93% relative to the crudeN-isopropylbenzothiazylsulpheneamide (of 94.3% purity) employed.

EXAMPLE 9 60 g of pyromellitic anhydride (0.275 mol) and 264 g ofcyclohexylbenzothiazylsulpheneamide of 98.1%

purity (0.98 mol) are introduced cold into a mixer equipped with aheating jacket, and stirred. The temperature of the mixture is raised toC and maintained at that temperature for 2 hours. The mass becomes pastyand then again hardens, whilst still remaining pasty. After cooling to20C., it slowly solidifies.

This crude mixture is thereafter treated with 1.1 litres of a normalaqueous sodium hydroxide solution for 2 hours at 20C. Filtration,washing and drying yields 207 g ofcyclohexyl-bis-(benzothiazylsulphene)amide, melting at l26127C. Thisrepresents a yield of 96.3% relative to the crudecyclohexylbenzothiazylsulpheneamide employed.

I claim:

1. Process for preparing a bis-(benzothiazylsulphene)amide of generalformula:

in which R is alkyl of l to 12 carbon atoms, cyclopentyl or cyclohexyl,-wherein a benzothiazylsulphcncamide of general formula:

SNHR

is reacted with maleic anhydride, succinic anhydridc, glutaricanhydridc, phthalic anhydridc, or pyromellitic anhydride.

2. A process according to claim I wherein the molar ratio ofbenzothiazylsulpheneamidc to anhydride groups is substantially 2:1.

3. A process according to claim 1 wherein the reaction is carried out inthe presence of an inert solvent.

4. A process according to claim 1 wherein the reaction product istreated with an aqueous alkaline solution and the insolublebis-(benzothiazylsulphene)amide separated form the solution containingimpurities.

S. A process according to claim 1 wherein a benzothiazylsulpheneamide inwhich R represents cyclohexyl, isopropyl or tert.-butyl is heated at 60l10C in the presence of about V2 a molar proportion of phthalic anhydridcor malcic anhydride or about A of a molar proportion of pyromclliticanhydride for about V2 to 2 hours.

6. A process according to claim 5 wherein the reaction product is washedwith an aqueous sodium hydroxide solution at about 10 to 30C and theinsoluble bis- (benzothiazylsulphenc)amide separated from the solutioncontaining impurities.

1. PROCESS FOR PREPARING A BIS-(BENZOTHIAZYLSULPHENE)AMIDE OF GENERALFORMULA:
 2. A process according to claim 1 wherein the molar ratio ofbenzothiazylsulpheneamIde to anhydride groups is substantially 2:
 3. Aprocess according to claim 1 wherein the reaction is carried out in thepresence of an inert solvent.
 4. A process according to claim 1 whereinthe reaction product is treated with an aqueous alkaline solution andthe insoluble bis-(benzothiazylsulphene)amide separated form thesolution containing impurities.
 5. A process according to claim 1wherein a benzothiazylsulpheneamide in which R represents cyclohexyl,isopropyl or tert.-butyl is heated at 60*-110*C in the presence of about1/2 a molar proportion of phthalic anhydride or maleic anhydride orabout 1/4 of a molar proportion of pyromellitic anhydride for about 1/2to 2 hours.
 6. A process according to claim 5 wherein the reactionproduct is washed with an aqueous sodium hydroxide solution at about 10*to 30*C and the insoluble bis-(benzothiazylsulphene)amide separated fromthe solution containing impurities.